1. Field of the Invention
The present invention relates to a coil wire for a rotating electrical machine in which a covering member is covered around an element wire assembly formed by binding a plurality of element wires, and a coil body using the coil wire.
2. Description of Related Art
For example, PCT International Application Publication No. WO 2012/049775 discloses a conventional motor wire that is formed by winding a strip-shaped member in an outer peripheral surface of an assembled wire which is formed by binding a plurality of wires in a spiral form. The cited reference discloses that the strip-shaped member used in the motor wire is made of a metal, and the electrical resistance of the strip-shaped member is greater than or equal to that of the wire. The cited reference also discloses that the strip-shaped member allows the increase in durability of the motor wire when the motor wire is bent to form a coil, to keep a state where the plurality of wires are bound, and the reduction of generation of eddy current in the coil.
The motor wire disclosed in WO 2012/049775 has a structure such that the total length of the strip-shaped member elongates because the strip-shaped member that has relatively high electrical resistance is wound over the entire wire in the longitudinal direction in a spiral form. If the strip-shaped member elongates, then the length of path where the electric current flows elongates, and thus a resistance loss increases. Here, an eddy current loss means a power loss that occurs due to the flow of eddy current.